【摘要】 LAI是表征作物生长状况的重要指标之一。为了快速无损监测小麦LAI,设置了3个密度和4个氮肥水平以形成不同的小麦生长群体,利用无人机搭载的RGB相机获取田间图像,并同步取样测定LAI。在小麦越冬期、返青期、拔节期、开花期和灌浆期选取R、G、B构建的9种颜色特征指数,与实测的LAI进行相关性分析。结果表明,在小麦生长前期(越冬期、返青期),颜色指数与LAI的相关性均较弱,而到了生育后期(拔节期、开花期、灌浆期),所有颜色指数与LAI的相关性均达到了极显著水平。选出常用的指数、线性、对数、多项式和幂函数等模型中R~2最大的作为最终的估算模型,用以估算拔节期、开花期、灌浆期这三个时期的小麦LAI。通过实测的LAI对估算模型的验证,模型可靠且准确率较高。上述结果为作物田间LAI快速测量提供了新的手段。更多还原

【Abstract】 Crop LAI is one of the important indicators to characterize the growth status of crops. In order to monitor wheat LAI rapidly and nondestructively, 3 densities and 4 nitrogen fertilizer treatments were set in this study to form different wheat growth groups, and field images were acquired by RGB camera mounted by UAV, and LAI was measured by synchronous sampling. The 9 color characteristic indexes constructed by R, G and B were selected to conduct correlation analysis with the measured LAI during the overwintering stage, returning green stage, jointing stage, flowering stage and grouting stage of wheat growth. The results showed that, at the early stage of wheat growth(overwintering stage, and returning green stage), the correlation between color index and LAI was weak, while at the late growth stage(jointing stage, flowering stage, and grouting stage), the correlation between all color indexes and LAI reached extremely significant level. The model of maximal R~2 in the commonly used exponential, linear, logarithmic, polynomial and power function models was selected as the final estimation model to estimate wheat LAI in three periods: jointing, flowering and grouting stages. The estimation models were verified to be reliable and accurate by the measured LAI. These results provided a new means for rapid measurement of LAI in crop fields.更多还原